Fish oil reduces effectiveness of chemotherapy
Utrecht – Researchers at University Medical Center Utrecht have dealt a blow to the advocates of allegedly healthy fish oil. The substance which is again and again named as a helpful substance for cancer patients, seems instead to have an uniquely adverse effect on nearly all types of chemotherapy – making cancer cells insensitive to the treatment, the researchers report in Cancer Cell (Online publication, 13th September). The basis of the research was the observation, that chemotherapy seems to get less effective over time. It appears that chemotherapy is made ineffective by two types of fatty acid that are made by mesenchymal stem cells in the blood. Under the influence of cisplatin chemotherapy, stem cells secrete fatty acids which induce resistance to a broad spectrum of chemotherapies. The problem is: The fatty acids are also found in commercially-produced fish oil supplements containing omega-3 and omega-6 fatty acids as well as in some algae extracts. The researchers refer to the acids 'PIFAs' which stands for platinum-induced fatty acids. The researchers studied the effect of PIFA's in mice and human cells. The mice studied had tumours under the skin. In the experiments, the tumours became insensitive to chemotherapy after administration of normal amounts of fish oil. "We currently recommend that these products should not be used whilst people are undergoing chemotherapy", says Emile Voest, a medical oncologist at UMC Utrecht, who supervised the research.